oil pressure with 15w50

I added a SOS oil cooler and switched to 15w50 Mobil 1.

My OEM gauge usually reads 2 at idle, 4 cruising and 6 under full acceleration.

Now it reads 2 at idle, 4 cruising and 4 at full (on the track too).

Thinking about switching to Mobil 1 0w40 or RP 10w40 since the SOS oil cooler is doing a good job of keeping the temp in check.

Any thoughts????

I would get the 15W50 out ASAP. In discussions with the "Chief Engineer" at Mobil, who actually is considered the "Father of Mobil 1" he recommended I change out the 15W50 from a track car and either go back to the 10W30 or he thought is was even better to go to the 5W30.

He explained that the 15W50 had larger oil molecules (acting as ball bearings) and this offered no advantage at all, and could be worse.

HTH,
LarryB

But since Jim tracks his car regularly, I would think the 50W or even the 40W would help with the oil viscosity from breaking down, and the flash point

Did the advice from the the Father of Mobil 1 take that into consideration or was it for street driving recommendation?

Hrant said:

But since Jim tracks his car regularly, I would think the 50W or even the 40W would help with the oil viscosity from breaking down, and the flash point

Did the advice from the the Father of Mobil 1 take that into consideration or was it for street driving recommendation?

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Beleive it or not, he said 5W30. And yes we discussed this based on track use. I had used this in Pete's heavily tracked NSX, because I found on the last service the oil seemed to smell burnt. My thought was the oil was overheated in some way. I thought this would help. He explained to me that the source of any odd or burnt smell in the oil is always based on the fuel. (assuming a good mechanically functional engine). He also said the change to 15W50 was incorrect and recommended I go back to 10W30 (spec) or better yet, 5W30. I stuck with the 10W30, because it is the spec from Honda.

Although I was quite surprised, it was obvious this man knew what he was talking about.

Regards,
LarryB

I'm not sure whether the OEM gauge oil reading change is due to the 15w50 or the oil cooler since I did both at the same time. I just thought it was strange to see such a drastic change while out on track. Makes me go, hummmm.

I think I will go back to RP 10w30 then.

CL65 Captain said:

I'm not sure whether the OEM gauge oil reading change is due to the 15w50 or the oil cooler since I did both at the same time. I just thought it was strange to see such a drastic change while out on track. Makes me go, hummmm.

I think I will go back to RP 10w30 then.

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If you do you will know for sure if it is the oil cooler or the oil. Please keep us posted.

Regards,
LarryB

My oil analyses from Blackstone after switching from Mobil 1 10W/30 to Motul 10W/40 (5W/40 in winter) with the CTSC is still perfectly within the range and no particular issues have shown up over the last two years and 7+K miles.

My viscosity was in the range of 57-58 with Mobil 1 and now it is 65 at 210F and my flashpoint has gone up from 405-415F to 425F.

YMMV

The stock gauge won't tell you anything, invest in a real oil pressure and temperature gauges. I think 0W40 or 5W30 would be better for your NA application.

Larry Bastanza said:

I would get the 15W50 out ASAP. In discussions with the "Chief Engineer" at Mobil, who actually is considered the "Father of Mobil 1" he recommended I change out the 15W50 from a track car and either go back to the 10W30 or he thought is was even better to go to the 5W30.

He explained that the 15W50 had larger oil molecules (acting as ball bearings) and this offered no advantage at all, and could be worse.

HTH,
LarryB

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I partially have to disagree

Changing the cold viscosity from 15 to 10 or 5 I fully agree, however changing the warm viscosity to 30 I completely disagree, espec when the car is occasionally tracked.

I would never go lower than 40.

On my CTSC NSX (which sees spirited street driving and some easy track use) I use 5W-40.
On all of my Turbo cars (almost all have been used on full track days) I have used 5W-50 for many years.
I would never ever use a 10 or 5W-30 on a tracked car, in my opinion the 30 won't sufficiently be able to cope with extended high temp runs, serious risk of breaking the oilfilm as it will become extremely thin under high temps-high surface pressure with the engine running on full potential.

My choice of 5W-50 on my Turbo cars is based on extensive research that I did many years ago asking several oilspecialists from oilcompanies what would be their advice on best choice for combined street/track use.
Their advice
-for a NA street/track used car: 5W-40 full synth
-for a NA full racer (so no street use): 10-W60 full synth
-For a Turbo street/track used car: 5W-50 full synth
I was also told to NEVER use a 10W-60 in a turbo car as that oil will give a big risk of the Turbo failing as it is too thick for the turbo oil channels.

Mind you, this was about 14 years ago when full synth oil was quite new on the market and oilspecs have gone up a lot since then....
I however have sticked to the 5W-50 on all my high performance cars ever since and have never had any reason to change.

Only reason for putting 5W40 in the NSX in stead of 5W-50 has been that so many people here seem to be fixed on 5 or 10W30 and I didn't want to go too far off as I have little to no experience with Vtec engines and wondered if there is possibly a reason not to use a 50 grade on the Vtec system.

The orange cars ran 0W-20 in 3-6 hour endurance races.


If you have an oil temp and pressure gauge, you can better monitor your motor and if the temps are in check, light oil is fine. Keeping the oil cool keeps the viscosity where it needs to be, so it dosn't thin out and/or break down.

CL65 Captain said:

I added a SOS oil cooler and switched to 15w50 Mobil 1.

My OEM gauge usually reads 2 at idle, 4 cruising and 6 under full acceleration.

Now it reads 2 at idle, 4 cruising and 4 at full (on the track too).

Thinking about switching to Mobil 1 0w40 or RP 10w40 since the SOS oil cooler is doing a good job of keeping the temp in check.

Any thoughts????

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I actually have the same results running 5-40 and 5-50 in the nsx

CL65 - what did Terry Dyson say? And why aren't you using snake oil.. I mean RLI I've had good results thus far..

I'd say send in your current oil for a sample to Dyson or Blackstone and see what you get. If it looks good, then you're good. I also wonder whether the Mobile 5W-50 is type#3 and the 5W-40 is type#4...

Either way, get oil results and that is the real way to know whether it's protecting or not.

Oil pressure and temp gauge will tell you what the oil is really doing, but you already know all that and everything else in this post :biggrin:

Using the above graph with cSt Viscosity @100C, the Mobil 1 10W/30 on my oil analyses reads in the range of 9.4-9.8 in 3000 miles oil use mixed track street driving, whereas the Motul 8100 5W/40 reads 11.6-11.8.

I suspect that this means the readings show that oil temps with track use are getting close to 260F operating temp at their peak/max - pretty consistent with my SPA gauge readings. And shouldn't this make obvious that the 40w or even 50w helps for track use then?

As for the Koni Challenge using 0W/20, are those daily drivers too? Or better yet, how often to do they tear the motor down before the next race?

Hrant said:

Or better yet, how often to do they tear the motor down before the next race?

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Ding, ding, ding.... we have a winner.

Agree w/ Hrant here. For a frequently tracked car the higher viscosity is certainly going to help.

And the stock gauge will only get you in the general ballpark and, IMHO, really shouldn't be relied on as an accurate indicator of engine temp.

My. 02.

Hrant said:

As for the Koni Challenge using 0W/20, are those daily drivers too? Or better yet, how often to do they tear the motor down before the next race?

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They ran heavier 30W oil until WPC treating internal components (www.wpctreatment.com) which enabled them to use 0W-20. They can typically go over a season without rebuilding them.

I would imagine the stresses and heat in that environment far exceeds daily driving, and since its a light weight oil, it would be fine for that application as well (rather than a heavy weight used for daily driving).

FXMDBilly said:

They ran heavier 30W oil until WPC treating internal components (www.wpctreatment.com) which enabled them to use 0W-20. They can typically go over a season without rebuilding them.

I would imagine the stresses and heat in that environment far exceeds daily driving, and since its a light weight oil, it would be fine for that application as well (rather than a heavy weight used for daily driving).

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Just as I suspected but didn't want to immediately jump on
Putting these cars and the oil used into the topic is completely besides the point and comparing appels to pears.

A race engine is built from completely different materials, different tolerances, special surface treatments, has a fully different life expectancy during which it must perform to the max, doesn't matter if at the end of the race it explodes...........

We are here talking about NSX which are used under many very different circumstances with max relieablity and life expectancy in mind.
This is what the oil advices here are aimed at!

rsevo6 said:

Just as I suspected but didn't want to immediately jump on
Putting these cars and the oil used into the topic is completely besides the point and comparing appels to pears.

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I tend to agree. In general, asking for advice on engine oil online is some-what like asking what style of shirt is the best. Someone from CA is going to tell you a designer muscle T-Shirt, while someone from Alaska is going to say you just need a wool sweater from Wall-Mart. Another is going to say a V-Neck Fleece is fine, but you should still wear a turtle neck under it in case you work up a sweat by mid-day. Then the astronaut chimes in, and says in his pressurized space suite... the regulated water-cooled cool-shirt has actually worked just fine for him, and that's what NASA uses.

While "tracking" I suppose at least narrows it down a bit... in the end, the discussion still inevitably gets randomized and frequently possesses little value.

rsevo6 said:

We are here talking about NSX which are used under many very different circumstances with max reliability and life expectancy in mind.
This is what the oil advices here are aimed at!

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Even "optimum" for a pro engine builder with decades of experience looks like this: there is no best. Only compromises. No guarantees, but his experience suggests that X should be ok for you.

Look. You guys can call all the vendors you want, and get 25 different vendors/reps giving you 10 different convoluted answers. Just realize that some companies advertised 30W race oils are fairly close in spec to another's general purpose 40W- so you are not always really comparing apples to oranges tossing weights around. Sometimes formulations are devised strictly so they can be labeled as a specific weight oil. Understand that whatever advice they are giving you, is probably based on some other application..

You can rely on forum fishing. Get another 40 different answers from 40 different members with "track experience". Just remember, like the brake pad discussion threads- when someone says they have had "great results" with the Axxis Ultimate brake pads.... or the factory 10W30 spec is the right choice per the owners manual... or that they track too and the factory oil change interval is certainly MORE than adequate... well... I can usually get a pretty good idea of what is really going on behind the scenes fairly quickly. If I relied on forums for my track advice all these years, shit- my car would never run!

A step in at least the right direction- you should talk to fellow established racers, builders, motorsports outfits. However, even then... take it with a grain of salt. Recognize that a race oil that one racer swears by and is all the rage in his spec or hotly contested limited class to free-up that last 2hp in a sprint- is not nearly the same goal as trying to optimize additives for ultimate protection in a 24hr. endurance race. Further, a race engine is often indeed different than a stock engine depending on what has been done, so realize that perhaps their recommendation/experience is completely irrelevant for what you are doing. Last, did you ever think that maybe some racer/vendor is really just plugging for his sponsor and a competing cheaper product with identical spec is just fine too? I've seen that too.

My point to all this... you really need to consider the source.

While most people are well intentioned in their responses.... real experience from running your own car and achieving good results is what is going to matter & count for the most. If you are going to take general advice, at least defer to those who run, or have at one time ran in a remotely similar context- and even then get the full story so you can make good decisions.

Picking a oil weight for track isn't rocket science: just go with the facts. What are your actual operating temps on course being experienced, how long are they sustained for, and then decide what you plan to optimize for (performance, protection, etc...). Look at honestly how you are using your car. Are you mostly street driving, mostly track driving, racing? Do you trailer your car? Do you mind letting it idle for 20 minutes? Are their any special design considerations for the engine? To what extent is the equipment really being pushed- stresses are often exponential so that point probably deserves special attention.

These are the core points that are really vital to the discussion. If you don't yet have a real working water & oil temp gauge in your track car- then as Billy mentioned, that is the first place to start so you can begin to monitor your temps and keep logs.

Ultimately, this is what it all boils down to when it comes to reliability and engine protection: picking a suitably rated oil (i.e. the theory) is actually the easy part. In most cases, the manufacturer has already done the hard work for you as the intended operating viscosity is known. What really counts for something is who is actually pushing the application to the the limits- year after year, on-course, under constant duty and not blowing up engines, transmissions, etc...

rsevo6 said:

Just as I suspected but didn't want to immediately jump on
Putting these cars and the oil used into the topic is completely besides the point and comparing appels to pears.

A race engine is built from completely different materials, different tolerances, special surface treatments, has a fully different life expectancy during which it must perform to the max, doesn't matter if at the end of the race it explodes...........

We are here talking about NSX which are used under many very different circumstances with max relieablity and life expectancy in mind.
This is what the oil advices here are aimed at!

Click to expand...

Which is exactly why I posted a picture of a showroom stock racing car rather than a GT, Prototype, or highly built car. You would be surprised how stock and limited the rules are for that class, no change in internal components unless specifically allowed (rare), stock compression, and running over a season shouldn't be that hard for many of the engines. Heck, there are cars out there with bone stock junkyard motors. So yes the photo of that car is much more relevant than what your thoughts of "race motors" are.

John@Microsoft said:

A step in at least the right direction- you should talk to fellow established racers, builders, motorsports outfits. However, even then... take it with a grain of salt. Recognize that a race oil that one racer swears by and is all the rage in his spec or hotly contested limited class to free-up that last 2hp in a sprint- is not nearly the same goal as trying to optimize additives for ultimate protection in a 24hr. endurance race. Further, a race engine is often indeed different than a stock engine depending on what has been done, so realize that perhaps their recommendation/experience is completely irrelevant for what you are doing.

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Agreed, and while the Koni Challenge ST class is pretty stock, lighter weight oil does free up a few HP and is accomplished through a metal surface treatment (WPC) that is a great product that increases the longevity of motor components. Whether for a street car, race car, endurance racing car, this is a not very well known but impressive product that should be aware of.

John@Microsoft said:

Last, did you ever think that maybe he is just plugging for his sponsor and a competing cheaper product with identical spec is just fine too? I've seen that too.

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Is that what you think I was doing? What were you referring to 'competing cheaper product'?

While I was spreading awareness of a product that should be better known and relevant to longevity of street cars and racecars alike, engine and transmission components, etc... I find it relevant for the ability of a relatively stock motor running lightweight oils reliably by keeping the temperatures in check.

John@Microsoft said:

Ultimately, this is what it all boils down to when it comes to reliability and engine protection: picking a suitably rated oil (i.e. the theory) is actually the easy part. What really counts for something is who is actually pushing the application to the the limits- year after year, on-course, under constant duty and not blowing up engines, transmissions, etc...

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And WPC is a process that should be considered from pistsons, rings, rods, main & rod bearings, synchros, gears, etc... when rebuilding a motor or transmission, because they are tested and victorious in endurance racing (3, 6, 12, 24, 25hr races), and are proven to increase the longevity of motor and transmission parts. You especially should look into it for your own applications. While that Koni team and many other professional race teams have had success for years with it, FXMD is still in its first year of use and have had nothing but positive results from WPC.

But I agree with most everything else you said about choosing an oil. Get a temp and pressure gauge, then a cooler if you're oil temps are too high, and go from there.

FXMDBilly said:

Is that what you think I was doing? What were you referring to 'competing cheaper product'?

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No. My rant was intended to be in highly general / abstract terms, not to be taken personally. While I have had racers/reps/shops whom I felt were just "plugging" products at me; I have never gotten the sense that your specific advice on the forums to the community has been anything other than genuine.

FXMDBilly said:

And WPC is a process that should be considered from pistsons, rings, rods, main & rod bearings, synchros, gears, etc... when rebuilding a motor or transmission, because they are tested and victorious in endurance racing (3, 6, 12, 24, 25hr races), and are proven to increase the longevity of motor and transmission parts. You especially should look into it for your own applications. While that Koni team and many other professional race teams have had success for years with it, FXMD is still in its first year of use and have had nothing but positive results from WPC.

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Having run stock production engines, I don't have any personal experience with the treatment. I am not an engine builder, but it seems to me that if it decreases friction and as a result temps, increases efficiency & reliability- then this is certainly a positive and should be considered during an engine re-build. It also looks like a great cheating mod for spec classes. How often do they tear down transmissions anyway? :biggrin:

FXMDBilly said:

But I agree with most everything else you said about choosing an oil. Get a temp and pressure gauge, then a cooler if you're oil temps are too high, and go from there.

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Thanks.

I've been data-logging my temps under various conditions all year, giving the data to the right people, and have made changes where necessary. As we discussed, I plan to make significant changes in the heat management department when I go FI.

Jim,
I don't see any advantage of running heavier that a 15-40, which I run all year round. Only down side is I need to let the motor idle for a few minutes when it is cool to get some heat in it, and really mind the temps before I push the car hard. My motor is built on the loose end, bearings and pistons, so it was designed for a bit thicker oil too.

I agree with Larry, 50 wt oils are hard on motors which have not been built for them, leave it to the race cars.

I rep a line of oils(Dumonde Tech-great oil, shitty website:http://www.dumondetech.com/) if you are ever interested in trying some, LMK.

Dave

Hrant said:

I suspect that this means the readings show that oil temps with track use are getting close to 260F operating temp at their peak/max - pretty consistent with my SPA gauge readings. And shouldn't this make obvious that the 40w or even 50w helps for track use then?

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You would think so. But like the last oil thread revealed, their is always going to be a subset of people that swear on the bible that the Honda owners manual knows best. They will proclaim the general purpose 10W30 rating is the shizzat for tracking/racing, because quite frankly that's what they want to believe, and they will in turn shop around until they get the answer they want to hear.

rsevo6 said:

I partially have to disagree

Changing the cold viscosity from 15 to 10 or 5 I fully agree, however changing the warm viscosity to 30 I completely disagree, espec when the car is occasionally tracked.

I would never go lower than 40.

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I agree. Let's consider some real logs. Consider the chart below. Here is what I consider to be a typical scenario. Early morning, about 12 laps or 20 minutes here. Ambient at 59 degrees, the high was only 70 degrees on June 14th. Pushing the car around decently. Consider this- with the Accusump, 8 quarts total system capacity, and various other misc cooling mods on my race car (which the average DE day enthusiast probably doesn't have on their sports car.... ducted hoods, NACA ducts, insulation, modified cooling system, gutted trunk, etc...) we are already looking at ~240 some odd degrees.

Now, per the SAE standard, an oil is considered to be a 30 weight in the range of 9.30-12.49 cST at 100C. M1 5 or 10W30 has a spec rating of 10-11.3 - so their 5W30 is right about in the middle, so we'll use that.

Plug the numbers in, and at the peak recorded operating temp of 246 degrees, the M1 5W30 would really have an effective viscosity of 7.3 cST to protect your vital engine parts. In short, even in this modest case study, the M1 5W30 would have thinned-out to an effective 20 weight during operation.





Another data point. Let's raise the bar a notch. What can a warm summer mid-afternoon look like even just dolling around? Well, it was 84 degrees peak on May 17th at the time this evening log was taken (it's probably that by breakfast for many of you in the desert). The large dips/spikes coincide with HPDE traffic as I get no air flow to my pan when I am off-pace. However, note that after about lap 1 this chart pretty much begins where the last peaked off in terms of average temps; even despite the fact that I wasn't racing. Another interesting point to this chart- you can be harder on your equipment and drive slower.

Do the math. Given the same M1 5/10W30 weight product, about 4.7-5.5 cST, so it would have thinned out to a 10 operating weight at this point! Good thing I don't have that in there!




So I think this all begs the question... what does worse case look like? Remember, I have very mild conditions in my region. What happens when you are racing for 40 minutes in 105F? What happens if it is really hot and you decide to run two sessions back to back, scrub an outlap, sit idling in the hot pits, or check yourself into a 24hr Enduro?

My experience, 265 is not in anyway uncommon for a probe in a stock NSX pan. That is consistent with other people's experience. Even with the thicker oil, you are going to be nestled at the upper allowable limit. If your cooling system is not performing ideally, if it creeps hotter, if you are nose to tail and not getting enough airflow across your radiator, if you are just slow and reving it up all the time, if you are running rich..... and you have thinned the hell out of a 30W... your charts are going to look a lot worse than mine as it shears, and 160C / 320F is possible at which point you are going to basically be running a 0 weight oil through your engine and seriously compromising your protection. Maybe time to look at that HTHS rating? That's what NA looks like.

For you FI guys, think about the heat. Why do you think Rob Morrison had like $5,000 into his cooling system in his supercharged NSX? You think RTR went by the factory manual? Hell no. Before I go FI, I plan to add a crap ton of supporting mods before cramming in 35% more air and fuel in each cylinder.

Conclusions- Given any significant, sustained track/race usage, forget the owners manual knows what fill is best here. While the manufacturers intended operating viscosity is correct and what you want - the specified weight spec is simply not intended for the operating temps customarily encounted during tracking/racing. Leave the general purpose 30 weight A1 oils for the blvd. where they belong. What matters with weight is the viscosity at the actual operating temps on course. Do consider the HTHS rating.

My 0.02

My whole point of this thread is because when I added the oil cooler and 15w50 my OEM gauge readings were very different (lower). I had run RP 0w40 in the spring on the track and they were "normal".

So until I add gauges, I think I will run a 40w this weekend to see if it's the 15w50 or oil cooler.

I would have to mail order (no time for this weekend) to get a 5w40 or 15w40, so my choices are RP 0w40, RP 10w40 or Mobil 1 0W40. Looks like OAT this weekend are going to be in the low 70s. :smile:

CL65 Captain said:

My whole point of this thread is because when I added the oil cooler and 15w50 my OEM gauge readings were very different (lower). I had run RP 0w40 in the spring on the track and they were "normal".

So until I add gauges, I think I will run a 40w this weekend to see if it's the 15w50 or oil cooler.

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I would speculate that it is probably the oil cooler/plumbing, or the sender- not the oil. Our setups are actually very similar and my pressures are healthy on course.